In this pilot we propose to recruit 88 older (65 - 79 yrs) men (n=48) and women (n=40) at risk for disability and with indications for weight loss according to NIH guidelines. All will be enrolled in a dietary intervention designed to generate a caloric deficit of 500 kcal/day for a 4 month period. All will receive supplemental vitamin D and calcium. These participants will be randomized into one of 4 groups: